The Special Boat Service

In the past few weeks, the normally low-profile Special Boat Service has been involved in two major operations - securing Bagram airbase in Afghanistan and boarding a frigate suspected of carrying explosives and biological weapons in the Channel just before Christmas. But most of the time, the SBS lurks in the shadow of its better-known counterpart, the Special Air Service.

About 200 commandos - drawn from the Royal Marines - make up the SBS at any one time. They regard themselves as even fitter than the SAS. Specialists in counter-terrorism, beach reconnaissance, sabotage, oil platform and large ship assault, they do most things the SAS does, but may swim 10 miles or carry a canoe as well. They have been 'mainly loners and survivors, individualists with strength of character', says former member Peter Mercer in his book Not by Strength, by Guile (Blake, £5.99).

Income: Salaries are as in the Royal Marines, basic pay ranging from £12,070 to £35,420 below officer level. SBS members are likely to earn the higher end, with top-ups for particular skills and various allowances.

Pension: The Armed Forces pension scheme is attractive, producing pensions of 32 per cent of final salary after 22 years' service below officer level, slightly more for officers. Retirement age is 55, but pensions can be drawn earlier.

Perks: Ordinary perks such as paid holiday are not of particular importance to the kind of person who joins the SBS. More important is the handling of sophisticated and powerful kit. With his night-viewing aids, satellite navigation systems, laser-guided weapon-sighting systems and perhaps control of a mini-submarine, one man can be handling technology worth millions on one night out. Although some people will be involved in just a couple of active missions a year, all retain remarkable levels of fitness. The super-fit former Liberal Democrat leader Paddy Ashdown demonstrates how the services fitness obsession becomes a lifelong habit.

The camaraderie engendered in the SBS does more than give a nice, cosy feeling; it is officially encouraged and helps save lives. And if you like playing expensive games, the SBS is the place: an annual exercise could be taking control of an oil rig which has, supposedly, been taken over by terrorists.

Disadvantages: This is no job for people who cannot survive for days in the wild, cooking worms in tobacco tins and either staying still or covering large distances at night. Exiting from and re-entering submarines is a dangerous job. More SBS operatives die in training than in active service.

Those that survive find their career is usually over at 40, when they are past their physical peak. Getting back into Civvy Street can be difficult for men used to such high levels of commitment. Some used to pick up the pen on retirement - there have been at least 30 books on the squadron - but they were all forced to sign confidentiality clauses in 1997.

The future: Poor communications with the SAS undermined their joint efforts in the Falklands War and other campaigns, resulting in talk of amalgamating the units. A merger is seen as inevitable by some.

My view: Duncan Falconer

'Every operative in special forces wants that first kill,' says former SBS operative Duncan Falconer, author of First Into Action (Warner, £7.99). 'It's like a baby touching the cooker - you don't really know what it's like until you do. Afterwards, you either get less sensitive to it or are disgusted.' In a 20-year career, Falconer was sent to Northern Ireland, the US, the Mediterranean and elsewhere. In his book he highlights the frequent lack of cohesion between the top brass, planners and operatives - particularly in Northern Ireland: 'Some of these self-generated operations were nothing more than job-creation schemes.'